System for proportioned liquid dispensing

Abstract

A system for proportional liquid dispensing of two liquids, the first of which can comprise the main flow drinking water supplied to livestock or poultry and the second of which can comprise controlled quantities of medication or nutrient to be introduced into the drinking water. Comprising the system is a solenoid operated pump for discharging controlled quantities of the second liquid into the main flow. A flow meter emits an electrical signal of the main flow rate at any given time while an optical pressure sensor emits an electrical signal indicative of the static pressure of the main flow. Logic circuits combine the flow rate and pressure signals for varying pump operation to controllably maintain a predetermined mixture ratio of the two liquids.

We claim: 
     
       1. A dispensing system for proportional mixing of selected liquids comprising: a flow meter adapted to be installed in a first conduit containing a flowing source of a first liquid to be mixed, said flow meter being characterized as providing an externally emitted signal correlated to the flow rate being encountered;   an energizeable pump operably arranged for its discharge to be connected to said first conduit downstream of said meter;   a second conduit connected to the intake of the said pump for receiving a quantity of a second liquid to be mixed with said first liquid;   a pressure sensor adapted to sense pressure values of said first liquid in said first conduit and to emit an output signal correlated to changes in the pressure being sensed; and   control means operable to receive the emitted signals from both said pressure sensor and said flow meter for varying the operation of said pump in controlled correlation to the combined values of said signals.   
     
     
       2. A dispensing system in accordance with claim 1 in which said meter signal is operative to initiate operation of said pump and after pump operation has been initiated said meter signal and said pressure signal are at least partially offsetting with respect to continuing operation of said pump. 
     
     
       3. A dispensing system in accordance with claim 1 in which said control means includes a timing circuit, and said pressure sensor operatively emits a pressure signal effecting linear modification of said timing circuit in correspondence to changes in pressure sensed by said pressure sensor. 
     
     
       4. A dispensing system in accordance with claim 3 in which said pump is reciprocably operable for discharging a predetermined quantity of said second liquid per stroke and said control means is operative to vary the number of pump strokes in correlation to a mixture ratio to be maintained between said first and second liquids. 
     
     
       5. A dispensing system in accordance with claim 4 in which said first liquid comprises water and said second liquid comprises a liquid mixture of predetermined content to be controllably added to said first liquid. 
     
     
       6. A dispensing system in accordance with claim 3 in which said pressure sensor comprises a Bourdon tube having a free end displaceable in a predetermined path in response to pressure changes being sensed and an optical sensor positioned opposite the displacement path of said Bourdon tube for optically sensing displacement thereof and for emitting said pressure signal to said timing circuit in correlation to the measurement of said sensed displacement. 
     
     
       7. A dispensing system in accordance with claim 6 in which said optical sensor comprises a transmitter-receiver for transmitting a light source to an indexed reference location on said Bourdon tube and to receive reflected light from said reference location for emitting said pressure signal. 
     
     
       8. A dispensing system in accordance with claim 7 in which said control means is effective to operate said system in a controlled cycle sequence including priming said pump, discharging said second liquid into said first liquid, cleaning said pump and backflushing said pump. 
     
     
       9. A dispensing system in accordance with claim 7 in which said pump is reciprocably operable for discharging a predetermined quantity of said second liquid per stroke, said system includes a reservoir containing a supply of said second liquid and said second conduit has an intake extending in flow communication with said reservoir for conducting a predetermined quantity of said second liquid to said pump with each operating stroke of said pump. 
     
     
       10. A dispensing system in accordance with claim 9 in which said first liquid comprises drinking water to be supplied to livestock or poultry and said second liquid comprises a health supplement to be supplied to said drinking water. 
     
     
       11. A dispensing system in accordance with claim 9 including air ventilation means associated with the intake of said second conduit for diverting air in said second liquid away from said intake. 
     
     
       12. A dispensing system in accordance with claim 11 in which said air ventilation means includes a float assembly operative for indicating an existing level of said second liquid in said reservoir and said air ventilation means is operatively effective to divert air in said second liquid away from said float assembly. 
     
     
       13. A dispensing system in accordance with claim 12 in which said air ventilation means includes at least one exhaust port through which the diverted air is disposed of.